I think the best way to build the culture is try to at the best you can show the value and do it yourself initially. Whether that's usability testing, user interviews, surveys. Like Amy said below, you can then present out. The one thing I've seen that is the most valuable is showing video interview or usability footage, typically that brings an A-HA moment.

I think this is similar to doing evangelizing of UX in any organization. In the past my team has done a Brown Bag Lunch for UX design and research in general (so, not specifically user research), booking an auditorium, printing posters, and encouraging folks we directly work with to attend. We got a really good turn out and it just gave folks awareness of the organization and what we do.